The present invention is directed to ramps or runways for trucks or trailers which facilitate the loading and unloading of vehicles or heavy machinery and equipment.
A truck or trailer provided with a pivotally mounted ramp or runway must be provided with fluid actuated means capable of raising and lowering the ramp or runway with respect to the ground and the bed of the truck or trailer. The elevating means usually embodies a piston and cylinder structure and the weight of the payload to be handled by the ramp or runway determines the size and number of piston and cylinder devices. The elevating means must also be capable of maintaining the ramp or runway in an elevated position with or without a load thereon.